氟、氯对热液钨、铜成矿的制约-以江西德兴铜矿、大吉山钨矿为例

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	氟、氯对热液钨、铜成矿的制约-以江西德兴铜矿、大吉山钨矿为例
其他题名	Chlorine and Fluorine Control on Copper and Tungsten Mineralization in Hydrothermal Deposits-Cases of Dexing Porphyry Copper Deposit and Dajishan Tungsten Deposit in Jiangxi province
	蒋国豪
	2004
学位授予单位	中国科学院地球化学研究所
学位授予地点	中国科学院地球化学研究所
学位名称	博士
学位专业	地球化学
关键词	矿化剂热液矿床花岗岩质岩石 f Cl元素对分异配分系数铜广斑岩型铜矿大吉山钨矿床
摘要	矿化剂在热液矿床成矿过程中的重要作用一直为人们所关注，矿化剂地球化学行为直接影响成矿元素的富集成矿，不同的矿化剂元素可能对金属成矿具有一定的专属性。本文以著名的江西德兴铜厂超大型斑岩铜矿床和大吉山钨矿床作为研究对象，研究F、Cl与W、Cu成矿的关系。主要的认识如下：（1）F在花岗质岩浆中，可以降低岩浆的粘度、密度、固液相线温度、改变熔体结构，而Cl对熔体结构没有多大的影响。F在流体一花岗质熔体相间，绝大多数配分系数小于1.0，趋向于熔体相中配分，DF随体系中F浓度的升高而增加。Cl在流体一花岗质熔体相间的配分系数均大于1.0，且Dc1 随体系中Cl浓度的升高而增大·Cl强烈地趋向富集于流体相中。（2）Cu在流体一花岗质熔体作用过程中，铜总趋向于流体相中分布（DCu都大于1）。特别是在富Cl流体中Cu浓度较高，说明在富含Cl的热液流体能够从共存的熔体中活化迁移出大量的 Cu，S的加入DCu有降低的趋势。钨趋向于熔体相中富集，其配分系数大多小于1.0。（3）德兴铜厂花岗闪长斑岩属钙碱性系列岩石属I型花岗岩类，具有埃达克岩的特征。岩浆来源于深部，在结晶演化过程中发生了围岩物质的混染，这种高铜含量围岩的混染使成矿物质在岩浆中得到富集，有利于铜的活化、迁移。在铜厂岩体不同的蚀变带中，SiO2、K2O、Cu、Mo等从新鲜斑岩甚至弱蚀变带中带出，而在强蚀变带强烈富集，Cl同样有在强蚀变岩石中富集的趋势；而Na2O、Fe从斑岩体中带出，进入流体相中，流体中大量Fe的存在，有利于铜的沉淀、富集成矿。（4）德兴铜厂斑岩体微量元素和稀土元素地球化学特征表明，该岩体发生了流体一熔体作用，分异出来的流体是一种相对富氯的流体，同时成矿流体的流向是从岩体中心向接触带方向流动。（5）大吉山花岗岩具有高SiO2、A/CNK值，显示过铝质特点。黑云母花岗岩是壳源花岗岩但又受到慢源岩浆或慢源流体的影响。随着花岗岩的演化（从I→II→III）SiO2、K2O＋Na2O逐渐增加，ΣFe、Al2O3、CaO、F含量降低，为成矿提供了大量的矿化剂（F）和沉淀剂（Fe、Ca）。Eu负异常从I至III阶段花岗岩逐渐加强，表明该岩浆经历了高度的分异演化。（6）大吉山花岗岩类稀土元素具有“四重效应”配分的特点以及微量元素对玲Rb、Y/Ho、Zr/Hf以及Nb／Ta发生明显分异，暗示在花岗岩岩浆的演化过程中，经历了充分的流体一熔体作用，同时分异出大量富含F、W等矿化剂元素和成矿元素的热液流体，致使钨矿的形成。大吉山石英脉型钨矿的成矿年龄大约在155 Ma。（7）通过对成矿流体和花岗质岩石黑云母、白云母中卤素相对逸度的研究（log(H2O/fHCl）fluid、log（fHF/fHCl）fluid）发现，铜厂斑岩型铜矿床的成矿体系是相对富氯体系，而大吉山石英脉型钨矿床成矿体系相对富氟，同时氟可能主要迁移W、Sn、Nb、Ta等金属元素。（8）结合斑岩型铜矿床成矿流体特征，铜主要以C1的络合物形式存在和迁移，迁移形式主要是CuCl0、CuCl2等。石英脉型钨矿床中，钨主要以钨酸、钨酸盐及其离解形式存在和迁移，如WO42-、HWO4-、NaHWO4、Naw伍．等；在高度富氟的成矿流体中，钨的氟氧络合物（如WO3F-，WO2F42-等）对钨迁移也具有重要的作用。因此，不同矿化剂类型具有一定的成矿专属性，热液铜矿床主要与Cl、S有关，而热液钨矿床大多与F有关。
其他摘要	In recent years, people began to pay attention to the importance of mineralizer in the process of the metal elements ore-forming. Geochemical behaviors of mineralizer affect the metal elements to form deposits to some degree, and different mineralizers have its mineralization speciality to different ore-forming elements. Generally magmatic hydrothermal Cu and Au deposits enrich Cl and S, but W and Sn deposits are rich F systems. In this paper, in order to study the relationship between the Cu, W and. Cl, S, F, Tongchang porphyry copper deposit and the Dajishan tungsten deposit are selected as the studying objectives, detailed investigations have been conducted into the geological and geochemical characteristics of the granitic rock, biotite, trace element and REE geochemistry, fluid inclusion geochemistry and the partitioning coefficients of the F, Cl, Cu, W. Based on these data, the following conclusions are drawn: Fluorine can reduce the viscosity and density of magma, temperature of solide-liquidus line and change the melt frame, but Cl has little effect on the melt.- Chlorine tends to be partitioned into the fluid phase while fluorine shows a strong tendency to the melt phase. Dp increases with the fluorine content increasing, and so does the Dei. Between the granitic melts and coexisting aqueous fluids, Cu strongly partitions toward the fluid. In contrast, W strongly partitions toward the melt. In particular Dcu linearly increases with the Cl concentration in the fluid, indicating that Cl can transport enough copper from the melt or other source bed to form the deposits. But Dcu decreases with the S added in experimental system. Tongchang granodiorite porphyry belongs to calc-alkali granite, also has: characters of the Adakites. Magma materials coming from the mantle, during the fractional crystallization, there exists contamination of the wall-rock. This process was propitious to enrich, activate, transport the copper. In different alteration granodiorite porphyry, SiO2> K.2O> Cu-. Mo are depleted in the fresh and weakly altered rock, and are enriched in the strongly altered rock, Cl is also enriched in the strongly altered rock. But Na2O and Fe are extracted from the porphyry into the ore-forming fluid, especially the presence of Fe is in favor of Cu deposition. The trace elements and REE geochemistry of the Tongchang granodiorite porphyry indicate, there exists the reaction between the porphyry and the hydrothermal fluid. The hydrothermal fluid was Cl-enriched solution, and flowed from the porphyry center to contact zone. Dajishan granites have high S1O2 content and high A/CNK, show peraluminous granite characters. Granites belong to S-type granite, but the biotite granite was affected by the mantle or mantle fluid. With the evolution of the granitic complexes, the SiO2 and K2O+Na2O increase, but Fe, AI2O3, CaO and F decrease. It supplied more mineralizer(F) and precipitator(Fe,Ca) for mineralization. Strong negative 8 Eu shows the granites are high evolved granite. The tetrad effect of REE and the obvious fractionation between K-Rb, Y-Ho, Zr-Hf, Nb-Ta, and Sr-Eu in the Dajishan granites indicate that, the aqueous fluid pays an important role in the evolution of the granites, as well as indicate that there exist enough interaction between peraluminous melt and aqueous magmatic fluid. Furthermore the fluorine played a very important role in this process. By studying of ore-forming fluid and the micas (using the F, Cl contents in micas to calculate the halogen fugacity of the hydrothermal fluid, eg. Log (/H2O/jHCl)tluid and log(/HF//HCl)fluid), Tongchang porphyry copper deposit system is enriched in chlorine, however Dajishan tungsten deposit system is relatively enriched in fluorine, which transport W, Sn, Nb, Ta, et al. According to the characters of the porphyry copper deposits, copper is transported by chlorine, such as CuCl0 and CuCb-. For the tungsten deposits, tungsten is transported by tungstate, such as WO42-. HWO4-, NaHW04 and NaWCV- In the high content F solution, fluorine plays an important role in tungsten transport, and the complexes are WO3F-, WO2F42-. From this paper different mineralizer has its speciality for mineralization, e.g. hydrothermal copper deposits always are enriched in chlorine, while hydrothermal tungsten deposits often enrich fluorine.
页数	100
语种	中文
文献类型	学位论文
条目标识符	http://ir.gyig.ac.cn/handle/352002/3690
专题	研究生_研究生_学位论文矿床地球化学国家重点实验室
推荐引用方式 GB/T 7714	蒋国豪. 氟、氯对热液钨、铜成矿的制约-以江西德兴铜矿、大吉山钨矿为例[D]. 中国科学院地球化学研究所. 中国科学院地球化学研究所,2004.

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